Greenhouse gas inventory: A case of gas flaring operations in Nigeria

Inventories of the greenhouse gases (GHGs) emitted into the atmosphere through gas flaring are scarce; hence, the need for this study. Formulae reported by the Association of Petroleum Institute were used for estimating GHGs based on data (1965 to 2013) sourced from the national agency for information on gas production and flaring in Nigeria. Analytica® (4.5) was employed to estimate the uncertainty associated with the emission inventory using a Tier 2 method. In this study, 1.87 × 109 tons of CO2, 1.09 × 107 tons of CH4 and 37.41 tons of N2O were estimated to have been released into the environment through the flaring of 895.01 billion cubic metre (bcm) of gas (55.6% of the total gas produced) over the 49-year period. The homogeneity tests conducted on the CO2 data obtained from reputable institutions and those of this work showed that they are statistically unequal, though with a relatively strong positive correlation. Furthermore, the estimated CO2 in our study showed good agreement with those reported in previous studies and with the national GHG inventory. The uncertainty associated with GHGs estimation was −108.58% and 61.02%. Increased domestic utilization and export development of natural gas in the country are therefore proposed to reduce gas flaring and GHG emissions.